The '42 edition will be a world war game with the newest rule-set from the evolution of all the AA games.
AAE is going to be the European theater of the war, so the scope of the game may be deciding issue.
that being said, if you might like AA at all you’ll probably enjoy either of them or the others, each has it’s own unique spin.
If you can afford it, I’d say get AAE and then expand into '42 in the fall.
*-balance for any of the games is in the eye of the beholder. Because countries do not start with the same income or units the game is not balanced. But their opportunities to win bring the balance into reality and the dice rolls help to balance it. Unless you plan to start playing tourneys you probably need not listen to these conversations.
*-the questions about one or any of the games being broken are really not worth getting caught up in either, there was a thought that AAE was broken for years but appears that people just didnt’ spend the time coming up with strategies. Turns out the counter to it being broken was quite simple.
If you hang out on any site about AA long enough you will find people complaining about everyone of the games being broken and just because someone says it, doesn’t mean you’ll hate it.
*i prefer to play face-to-face; just more fun to be in the room with friends playing, but between those times online will work too.